linux/fs/afs/super.c

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/*
* Copyright (c) 2002 Red Hat, Inc. All rights reserved.
*
* This software may be freely redistributed under the terms of the
* GNU General Public License.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Authors: David Howells <dhowells@redhat.com>
* David Woodhouse <dwmw2@cambridge.redhat.com>
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include "vnode.h"
#include "volume.h"
#include "cell.h"
#include "cmservice.h"
#include "fsclient.h"
#include "super.h"
#include "internal.h"
#define AFS_FS_MAGIC 0x6B414653 /* 'kAFS' */
struct afs_mount_params {
int rwpath;
struct afs_cell *default_cell;
struct afs_volume *volume;
};
static void afs_i_init_once(void *foo, kmem_cache_t *cachep,
unsigned long flags);
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 11:02:57 +02:00
static int afs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data, struct vfsmount *mnt);
static struct inode *afs_alloc_inode(struct super_block *sb);
static void afs_put_super(struct super_block *sb);
static void afs_destroy_inode(struct inode *inode);
static struct file_system_type afs_fs_type = {
.owner = THIS_MODULE,
.name = "afs",
.get_sb = afs_get_sb,
.kill_sb = kill_anon_super,
.fs_flags = FS_BINARY_MOUNTDATA,
};
static struct super_operations afs_super_ops = {
.statfs = simple_statfs,
.alloc_inode = afs_alloc_inode,
.drop_inode = generic_delete_inode,
.destroy_inode = afs_destroy_inode,
.clear_inode = afs_clear_inode,
.put_super = afs_put_super,
};
static kmem_cache_t *afs_inode_cachep;
static atomic_t afs_count_active_inodes;
/*****************************************************************************/
/*
* initialise the filesystem
*/
int __init afs_fs_init(void)
{
int ret;
_enter("");
afs_timer_init(&afs_mntpt_expiry_timer, &afs_mntpt_expiry_timer_ops);
/* create ourselves an inode cache */
atomic_set(&afs_count_active_inodes, 0);
ret = -ENOMEM;
afs_inode_cachep = kmem_cache_create("afs_inode_cache",
sizeof(struct afs_vnode),
0,
SLAB_HWCACHE_ALIGN,
afs_i_init_once,
NULL);
if (!afs_inode_cachep) {
printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
return ret;
}
/* now export our filesystem to lesser mortals */
ret = register_filesystem(&afs_fs_type);
if (ret < 0) {
kmem_cache_destroy(afs_inode_cachep);
kleave(" = %d", ret);
return ret;
}
kleave(" = 0");
return 0;
} /* end afs_fs_init() */
/*****************************************************************************/
/*
* clean up the filesystem
*/
void __exit afs_fs_exit(void)
{
unregister_filesystem(&afs_fs_type);
if (atomic_read(&afs_count_active_inodes) != 0) {
printk("kAFS: %d active inode objects still present\n",
atomic_read(&afs_count_active_inodes));
BUG();
}
kmem_cache_destroy(afs_inode_cachep);
} /* end afs_fs_exit() */
/*****************************************************************************/
/*
* check that an argument has a value
*/
static int want_arg(char **_value, const char *option)
{
if (!_value || !*_value || !**_value) {
printk(KERN_NOTICE "kAFS: %s: argument missing\n", option);
return 0;
}
return 1;
} /* end want_arg() */
/*****************************************************************************/
/*
* check that there's no subsequent value
*/
static int want_no_value(char *const *_value, const char *option)
{
if (*_value && **_value) {
printk(KERN_NOTICE "kAFS: %s: Invalid argument: %s\n",
option, *_value);
return 0;
}
return 1;
} /* end want_no_value() */
/*****************************************************************************/
/*
* parse the mount options
* - this function has been shamelessly adapted from the ext3 fs which
* shamelessly adapted it from the msdos fs
*/
static int afs_super_parse_options(struct afs_mount_params *params,
char *options,
const char **devname)
{
char *key, *value;
int ret;
_enter("%s", options);
options[PAGE_SIZE - 1] = 0;
ret = 0;
while ((key = strsep(&options, ",")) != 0)
{
value = strchr(key, '=');
if (value)
*value++ = 0;
printk("kAFS: KEY: %s, VAL:%s\n", key, value ?: "-");
if (strcmp(key, "rwpath") == 0) {
if (!want_no_value(&value, "rwpath"))
return -EINVAL;
params->rwpath = 1;
continue;
}
else if (strcmp(key, "vol") == 0) {
if (!want_arg(&value, "vol"))
return -EINVAL;
*devname = value;
continue;
}
else if (strcmp(key, "cell") == 0) {
if (!want_arg(&value, "cell"))
return -EINVAL;
afs_put_cell(params->default_cell);
ret = afs_cell_lookup(value,
strlen(value),
&params->default_cell);
if (ret < 0)
return -EINVAL;
continue;
}
printk("kAFS: Unknown mount option: '%s'\n", key);
ret = -EINVAL;
goto error;
}
ret = 0;
error:
_leave(" = %d", ret);
return ret;
} /* end afs_super_parse_options() */
/*****************************************************************************/
/*
* check a superblock to see if it's the one we're looking for
*/
static int afs_test_super(struct super_block *sb, void *data)
{
struct afs_mount_params *params = data;
struct afs_super_info *as = sb->s_fs_info;
return as->volume == params->volume;
} /* end afs_test_super() */
/*****************************************************************************/
/*
* fill in the superblock
*/
static int afs_fill_super(struct super_block *sb, void *data, int silent)
{
struct afs_mount_params *params = data;
struct afs_super_info *as = NULL;
struct afs_fid fid;
struct dentry *root = NULL;
struct inode *inode = NULL;
int ret;
kenter("");
/* allocate a superblock info record */
as = kmalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (!as) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
memset(as, 0, sizeof(struct afs_super_info));
afs_get_volume(params->volume);
as->volume = params->volume;
/* fill in the superblock */
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
sb->s_magic = AFS_FS_MAGIC;
sb->s_op = &afs_super_ops;
sb->s_fs_info = as;
/* allocate the root inode and dentry */
fid.vid = as->volume->vid;
fid.vnode = 1;
fid.unique = 1;
ret = afs_iget(sb, &fid, &inode);
if (ret < 0)
goto error;
ret = -ENOMEM;
root = d_alloc_root(inode);
if (!root)
goto error;
sb->s_root = root;
kleave(" = 0");
return 0;
error:
iput(inode);
afs_put_volume(as->volume);
kfree(as);
sb->s_fs_info = NULL;
kleave(" = %d", ret);
return ret;
} /* end afs_fill_super() */
/*****************************************************************************/
/*
* get an AFS superblock
* - TODO: don't use get_sb_nodev(), but rather call sget() directly
*/
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 11:02:57 +02:00
static int afs_get_sb(struct file_system_type *fs_type,
int flags,
const char *dev_name,
void *options,
struct vfsmount *mnt)
{
struct afs_mount_params params;
struct super_block *sb;
int ret;
_enter(",,%s,%p", dev_name, options);
memset(&params, 0, sizeof(params));
/* start the cache manager */
ret = afscm_start();
if (ret < 0) {
_leave(" = %d", ret);
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 11:02:57 +02:00
return ret;
}
/* parse the options */
if (options) {
ret = afs_super_parse_options(&params, options, &dev_name);
if (ret < 0)
goto error;
if (!dev_name) {
printk("kAFS: no volume name specified\n");
ret = -EINVAL;
goto error;
}
}
/* parse the device name */
ret = afs_volume_lookup(dev_name,
params.default_cell,
params.rwpath,
&params.volume);
if (ret < 0)
goto error;
/* allocate a deviceless superblock */
sb = sget(fs_type, afs_test_super, set_anon_super, &params);
if (IS_ERR(sb))
goto error;
sb->s_flags = flags;
ret = afs_fill_super(sb, &params, flags & MS_SILENT ? 1 : 0);
if (ret < 0) {
up_write(&sb->s_umount);
deactivate_super(sb);
goto error;
}
sb->s_flags |= MS_ACTIVE;
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 11:02:57 +02:00
simple_set_mnt(mnt, sb);
afs_put_volume(params.volume);
afs_put_cell(params.default_cell);
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 11:02:57 +02:00
_leave(" = 0 [%p]", 0, sb);
return 0;
error:
afs_put_volume(params.volume);
afs_put_cell(params.default_cell);
afscm_stop();
_leave(" = %d", ret);
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 11:02:57 +02:00
return ret;
} /* end afs_get_sb() */
/*****************************************************************************/
/*
* finish the unmounting process on the superblock
*/
static void afs_put_super(struct super_block *sb)
{
struct afs_super_info *as = sb->s_fs_info;
_enter("");
afs_put_volume(as->volume);
afscm_stop();
_leave("");
} /* end afs_put_super() */
/*****************************************************************************/
/*
* initialise an inode cache slab element prior to any use
*/
static void afs_i_init_once(void *_vnode, kmem_cache_t *cachep,
unsigned long flags)
{
struct afs_vnode *vnode = (struct afs_vnode *) _vnode;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
memset(vnode, 0, sizeof(*vnode));
inode_init_once(&vnode->vfs_inode);
init_waitqueue_head(&vnode->update_waitq);
spin_lock_init(&vnode->lock);
INIT_LIST_HEAD(&vnode->cb_link);
INIT_LIST_HEAD(&vnode->cb_hash_link);
afs_timer_init(&vnode->cb_timeout,
&afs_vnode_cb_timed_out_ops);
}
} /* end afs_i_init_once() */
/*****************************************************************************/
/*
* allocate an AFS inode struct from our slab cache
*/
static struct inode *afs_alloc_inode(struct super_block *sb)
{
struct afs_vnode *vnode;
vnode = (struct afs_vnode *)
kmem_cache_alloc(afs_inode_cachep, SLAB_KERNEL);
if (!vnode)
return NULL;
atomic_inc(&afs_count_active_inodes);
memset(&vnode->fid, 0, sizeof(vnode->fid));
memset(&vnode->status, 0, sizeof(vnode->status));
vnode->volume = NULL;
vnode->update_cnt = 0;
vnode->flags = 0;
return &vnode->vfs_inode;
} /* end afs_alloc_inode() */
/*****************************************************************************/
/*
* destroy an AFS inode struct
*/
static void afs_destroy_inode(struct inode *inode)
{
_enter("{%lu}", inode->i_ino);
kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
atomic_dec(&afs_count_active_inodes);
} /* end afs_destroy_inode() */